You will also lose sick leave, paternity leave (assuming you are a man!), company pension (if one exists) (you'll have to start a PRSA or personal pension, but the company can't pay into it as you are no longer an employee.
Add to this, you may have to register for VAT, if you are over the threshold, and charge VAT on your services at 21.5%
You have no union, no rights to employee legislation, and probably a contract subject to termination at a month's notice without additional compensation. In any liquidation, I believe you are an unsecured creditor, so are low on the list of getting any amounts owed.
You will also have to wait until your invoice is processed to be paid - sixty or ninety days is usual for many companies in Ireland.
You will have the additional expense of being tax-compliant, probably about a grand a year in accountancy fees, VAT returns etc.
All in all, you would want to be looking for 30-40% more to be contract than employee and then be charging VAT on top of that (which goes to the government and can be claimed back by your employer, so nets off to zero for the two of you).
Finally, and this is, to my mind the worst of all, you lose your rights to jobseekers benefit as you will only be paying class S PRSI. This will mean you are means tested on any benefit you get and if anyone who lives in your household is employed or even on other benefits (I believe) their means are taken into account before you get anything. There is a list of benefits available to class A PRSI vs. class S - you should look at it to see what you will not be entitled to.
This is in addition to the other things above, all of which apply, as far as I can see!
I don't mean to scare you, but there are a lot of pitfalls to being self-employed that you should know about up front. I could never advise anyone to become self-employed by choice in hard times.